In order to reduce the air-conditioning loads of buildings, vehicles such as bus and automobile, and rail cars such as electric car, the windows mounted these buildings or vehicles heretofore have required the functions of shielding near infrared ray (heat-ray) in the solar light and of insulating heat by reflecting heat-ray emitted from inside of a room. As glasses shielding or reflecting heat-ray, a heat-ray adsorbing glass obtained by introducing ions such as Fe, Cr and Ti by kneading action to add heat-ray adsorbing property to a glass, a heat-ray reflecting glass having metal oxide film formed by deposition, a heat-ray reflecting glass having a transparent thin film of indium-tin oxide (ITO) or tin oxide (ATO) formed by dry-plating, and a heat-ray shielding glass having a heat-ray shielding film (also referred to as Low-E film) obtained by lamination of a noble metal film/metal oxide film mainly consisting of metal oxide film/Ag film (Patent Document 1), have been developed, and put to practical use. Of these glasses or films, the Low-E film has functions (thermal insulation properties) of transmitting near infrared ray of the solar light (having relative short wavelength) and reflecting far infrared ray emitted from inside of a room (heater) to prevent the heat of the ray from escaping.
As these glasses shielding heat-ray (i.e., solar control glass), especially the glass having the Low-E film, a double glass having the structure that the glass shielding or reflecting heat-ray and another glass are arranged at a predetermined interval (through an air layer) such that these glasses face each other has been developed in order to improve thermal insulation property (Patent Document 2). Thereby, energy consumed by cooling and heating can be further reduced.
Further, a solar control glass enhanced in thermal insulation property and visible light transmittance, in which a coating layer comprising a particle of tungsten oxide and/or composite tungsten oxide (hereinafter referred to as (composite) tungsten oxide) and an UV-excitation color protection agent is formed on a glass plate, has been developed (Patent Document 3).
Further, it is known that the property absorbing infrared ray is found in an electrically-conductive polymer. Therefore, a transparent heat-shielding film comprising a surface protection layer, a heat-shielding layer containing the electrically-conductive polymer, a substrate, an ultraviolet ray absorbing layer and an adhesive layer has been developed (Patent Document 4).